Potable water is typically stored in large tanks or similar structures so it is available for use at a later time. Chlorine is often used in the treatment process to ensure the water is potable and remains safe for use after it leaves the treatment facilities. As such, the potable water has a residual chlorine concentration while in the distribution system and in storage tanks. While there are valves and other operational controls to regulate the amount of water that goes into water storage tanks, there may be an occurrence where too much water is pumped into a water storage tank due to control or valve malfunctions. When this happens, the excess water flows out of the water storage tank through an overflow pipe where it is discharged directly, or indirectly, onto the ground adjacent to the water storage tank. This can be an environmental issue because of the possible deleterious effects of the chlorine in the discharged water on plant and animal life. This is reflected in the regulations limiting the concentration of chlorine in water that can be discharged into the environment to less than 20 parts per billion in some areas of California.
In addition to free chlorine, certain chloramines, such as NH2Cl, are also used as a disinfectant in municipal water supplies. As used in this application, chlorine shall include both free chlorine and chloramines. Therefore, removing or neutralizing or eliminating chlorine using dechlorinating material will refer to material suited for use with one or both of free chlorine and chloramines.
In response to the requirement for removing, neutralizing or eliminating chlorine from water being discharged into the environment, various types of flow-through devices have been created. One type of flow-through device, sold as the Dechlor Demon by Hydro Flow Products, Inc., of Arlington Heights, Ill., uses an in-line device to divert a portion of the water flowing through the device into a mixing tank containing a concentrated dechlorinating agent. That water, which has excess dechlorinating agent, is then directed back into the in-line device where it mixes with and dechlorinates the main flow of water through the device. Another type of a water diverter flow-through device introduces a measured amount of a dechlorination chemical into water passing through a pipe. The device uses a similar principle as used to meter fertilizer to water flowing through a hose. A third type of flow-through device passes all the water through a cup-shaped screen containing dechlorination tablets for removal of the chlorine. One example of this type of device is sold by Saratoga Safeguard Solutions of Ballston Spa, N.Y., as the Hydro Hitch Eco-Suspender. All of these devices are typically used to treat water being discharged from a fire hydrant.